title: Meiotic pairing of B chromosomes, multiple sexual system, and Robertsonian fusion in the red brocket deer Mazama americana (Mammalia, Cervidae).
abstract: Deer species of the genus Mazama show significant inter- and intraspecific chromosomal variation due to the occurrence of rearrangements and B chromosomes. Given that carriers of aneuploidies and structural rearrangements often show anomalous chromosome pairings, we here performed a synaptonemal complex analysis to study chromosome pairing behavior in a red brocket deer (Mazama americana) individual that is heterozygous for a Robertsonian translocation, is a B chromosome carrier, and has a multiple sex chromosome system (XY₁Y₂). The synaptonemal complex in spermatocytes showed normal chromosome pairings for all chromosomes, including the autosomal and sex trivalents. The electromicrographs showed homology among B chromosomes since they formed bivalents, but they also appeared as univalents, indicating their anomalous behavior and non-Mendelian segregation. Thus, synaptonemal complex analysis is a useful tool to evaluate the role of B chromosomes and rearrangements during meiosis on the intraspecific chromosomal variation that is observed in the majority of Mazama species.
authors.affiliation: Núcleo de Pesquisa e Conservação de Cervídeos, Departamento de Zootecnia, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Campus de Jaboticabal, Jaboticabal, SP, Brasil.
authors.forename: C I
authors.initials: CI
authors.lastname: Aquino
authors.forename: V V
authors.initials: VV
authors.lastname: Abril
authors.forename: J M B
authors.initials: JM
authors.lastname: Duarte
mesh_terms: D000818:Animals; D002875:Chromosomes / Q000235:genetics*; D003670:Deer / Q000235:genetics*; D015321:Gene Rearrangement; D006579:Heterozygote; D008297:Male; D008540:Meiosis / Q000235:genetics*; D011110:Polymorphism, Genetic; D013090:Spermatocytes / Q000378:metabolism; D014178:Translocation, Genetic